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Neutral sphingomyelinases (nSMase) catalyze the hydrolysis of sphingomyelin in biological membranes to ceramide and phosphorylcholine Sphingomyelinases (SMase) are phosphodiesterases that catalyze the hydrolysis of sphingomyelin to ceramide and phosphorylcholine. Eukaryotic SMases have been classified according to their pH optima and are known as acid SMase, alkaline SMase, and neutral SMase (nSMase). Eukaryotic proteins in this family are nSMases, and are activated by a variety of stress-inducing agents such as cytokines or UV radiation. Ceramides and other metabolic derivatives, including sphingosine, are lipid "second messenger" molecules that participate in the regulation of stress-induced cellular responses, including cell death, adhesion, differentiation, and proliferation. Bacterial neutral SMases, which also belong to this domain family, are secreted proteins that act as membrane-damaging virulence factors. They promote colonization of the host tissue. This family belongs to the large EEP (exonuclease/endonuclease/phosphatase) superfamily that contains functionally diverse enzymes that share a common catalytic mechanism of cleaving phosphodiester bonds. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",